Pilot burner control system for a double burner oven or the like and method of operating the same

ABSTRACT

THIS DISCLOSURE RELATES TO A PILOT BURNER CONTROL SYSTEM FOR A BROIL BURNER OF A DOMESTIC OVEN OR THE LIKE WHEREIN THE BROIL BURNER AND THE BAKE BURNER ARE DISPOSED IN A SINGLE OVEN CAVITY THAT HAS A CONTROL DEVICE THAT IS ADAPTED TO SELECTIVELY INTERCONNECT A SOURCE OF FUEL TO EITHER THE BAKE BURNER OR THE BROIL BURNER. THE PILOT BURNER FOR THE BROIL BURNER IS ADAPTED TO BE CONTINUOUSLY SUPPLIED FUEL FROM THE SOURCE OF FUEL AND WHEN THE CONTROL DEVICE IS SET IN A POSITION TO OPERATE EITHER THE BAKE BURNER OF THE BROIL BURNER, AN AIR PUMPING DEVICE IS ENERGIZED TO FORCE PRIMARY AIR THAT IS NOT CONTAMINATED WITH COMBUSTION PRODUCTS CREATED IN THE SINGLE CAVITY OF THE OVEN DIRECTLY TO THE PILOT BURNER TO BE ENTRAINED IN THE FUEL FLOWING THERETO SO AS TO INSURE THAT FLAME MEANS WILL ALWAYS EXIST AT THE PILOT BURNER MEANS FOR THE BROIL BURNER AND WILL NOT BE SNUFFED OUT BY COMBUSTION PRODUCTS DURING THE USE OF THE OVEN.

Feb. 9, 1971 R|EHL 3,561,896

PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER OVEN OR THE LIKE AND METHOD OF OPERATING THE SAME 7 Sheets-Sheet 1 Filed] an. 14 1969 oooooo 3 FlG.l

HIS ATTORNEYS Feb. 9, 1971 RIEHL 3,561,896

PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER OVEN OR THE} LIKE AND METHOD OF OPERATING THE SAME Filed Jan. 14, 1969 7 Sheets$heet 2 5% l I 10-- \H 27 If 1024 105 i l 'wi g A L Y mgigg 114 26 T 7 v --84 L i r r41 42 INVENTOR FRED RIEHL I BY Fl 2 HIS ATTORNEYS Feb. 9, 1971 F. RIEHL 3,561,896

PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER OVEN OR THE LIKE AND METHOD OF OPERATING THE SAME F1186. Jan. 14, 1969 7 Sheets-Sheet 5 INVENTOR FRED RIEHL HIS ATTORNEYS Feb. 9, 1971 F. RIEHL 3,561,896

PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER OVEN OR THE LIKE AND METHOD OF OPERATING THE SAME Filed Jan. 14, 1969 7 Sheets-Sheet 4 INVENTOP FRED RIEHL dvuJn?duuh HIS ATTORNEYS Feb. 9, 1971 Rl 3,561,896

PILOT BURNER CONTROL SYSTE .0 DOUBLE RNER OVEN OR THE LIKE AND METHOD OPERATING T SAME Filed Jan. 14, 1969 7 Sheets-Sheet 5 NTOR F RIEHL QMMM HIS ATTORNEYS Feb. 9, 1971 F. RIEHL 3,561,896

. PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER OVEN on THE LIKE AND METHOD OF OPERATING THE SAME Filed Jan. 14, 1969 7 Sheets-Sheet s INVENTOR FRED RIEHL HIS ATTORNEYS F. RIEHL Feb. 9, 1971 a PILOT BURNER CONTROL SYSTEM FOR A DOUBLE BURNER 0vEN OR THE LIKE AND METHOD OF OPERATING THE SAME 7 Sheets-Sheet 7 Filed Jan. 14, 1969 INVENTOR FRED RIEHL HIS ATTORNEYS United States atent Int. Cl. F23n US. Cl. 431-42 28 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a pilot burner control system for a broil burner of a domestic oven or the like wherein the broil burner and the bake burner are disposed in a single oven cavity that has a control device that is adapted to selectively interconnect a source of fuel to either the bake burner or the broil burner. The pilot burner for the broil burner is adapted to be continuously supplied fuel from the source of fuel and when the control device is set in a position to operate either the bake burner or the broil burner, an air pumping device is energized to force primary air that is not contaminated with combustion products created in the single cavity of the oven directly to the pilot burner to be entrained in the fuel flowing thereto so as to insure that flame means will always exist at the pilot burner means for the broil burner and will not be snuffed out by combustion products during the use of the oven.

This invention relates to an improved pilot burner control system for a double burner oven arrangement or the like and to improved methods for operating such a control system or the like.

It is well known that fuel control systems have been provided for effectively directing a flow of fuel to either a bake burner or to a broil burner respectively disposed in a single oven cooking cavity or chamber, depending upon the position of a selector knob of a control device of the system. However, in the past, the pilot burner means for igniting the broil burner required an expensive electrical ignition means to be operated each time the broil burner is to be operated in order to insure ignition of the pilot burner means for the broil burner because during the normal use of the oven for a baking operation the combustion products produced during such a baking operation tended to snuff out the pilot burner means for the broil burner, as the same is located above the bake burner in the single cavity of the oven. Alternately, a complicated snorkel tube arrangement was provided to tend to direct fresh primary air to the pilot burner for the broil burner through an aspiration process caused by the flow of fuel passing to the pilot burner for the broil burner.

However, it has been found, according to the teachings of this invention, that primary air that is free of the contaminants of the combustion products of the oven can be forced by an air pumping means directly to the pilot burner for the broil burner only during the operation of the oven and that when the oven is not operating the primary air could be supplied to the pilot burner for the broil burner from the oven cavity itself.

In particular, one embodiment of this invention provides a pilot burner means for the broil burner wherein a first conduit means is adapted to continuously supply fuel from a source of fuel to the broil pilot burner to create certain flame means at the outlet end of the pilot burner means. A second conduit means of the pilot burner is so constructed and arranged that the same is in fluid communication with the first conduit means and is interconnected to an air pumping device which when operated 3,551,895 Patented Feb. 9, I971 will force primary air from a region that is free of contaminants of the oven to the pilot burner to be entrained in the fuel being directed thereto assure continuous burning of the pilot burner means during the operation of the oven. However, the second conduit means has opening means formed therein in such a manner that when the air pumping device is not operating because the oven is in an off condition thereof, the flow of fuel to the pilot burner, through an aspiration effect, draws primary air through the opening means in the second conduit means to be entrained in the fuel for maintaining combustion at the broil pilot burner.

Accordingly, it is an object of this invention to provide an improved pilot burner control system for a double burner oven arrangement or the like, the control system of this invention having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method for operating such a pilot burner control system, the method of this invention having one or more of the novel features set forth above or hereinafter shown or described.

Other objects, uses and advantages of this invention are apparent from a reading of this description, which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIG. 1 is a schematic view illustrating the improved control system of this invention.

FIG. 2 is an enlarged schematic view of part of the control system illustrated in FIG. 1 and illustrates schematically the control device utilized with the system of FIG. 1.

FIG. 3 is a cross-sectional view of the control device of the system of FIG. 1 and is taken on line 3-3 of FIG. 4.

FIG. 4 is a cross-sectional view of the control device of FIG. 3 and is taken on line 44 thereof.

FIG. 5 is an exploded perspective view of various parts of the control device of FIGS. 3 and 4.

FIG. 6 is a front view of the control device of FIGS. 3 and 4 with the selector knob and cooperating means removed to illustrate the control device in its off position.

FIG. 6A is a schematic view illustrating the disc valve member of the control device of FIGS. 3 and 4 when disposed in the off position of FIG. 6.

FIG. 6B is a cross-sectional view taken on lines 6B6B of FIG. 4 to illustrate the clutching member of the control device when the control device is set in its ofl position of FIG. 6.

FIG. 7 is a view similar to FIG. 6 and illustrates the control device in a baking position thereof.

FIG. 7A is a view similar to FIG. 6A and illustrates the disc valve set in the baking position of FIG. 7.

FIG. 7B is a view similar to FIG. 6B and illustrates the clutching member of the control device when set in the baking position of FIG. 7.

FIG. 8 is a view similar to FIG. 6 and illustrates the control device of FIGS. 3 and 4 set in its broiling position.

FIG. 8A is a view similar to FIG. 6A and illustrates the disc valve member set in the broiling position of FIG. 8.

FIG. 9 is an enlarged front view of the control knob means for the control device of FIGS. 3 and 4.

FIG. 10 is a side view of the improved pilot burner of this invention.

FIG. 11 is a top view of the pilot burner illustrated in FIG. 10 with certain parts thereof being broken away.

FIG. -l2 is an exploded perspective view of the pilot burner of FIG. 10.

While the various features of this invention are hereinafter described and illustrated as being particularly adaptable to provide a pilot burner control system for a double burner domestic oven or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide pilot burner means for operating other control systems or the like.

Therefore, this invention is not to be limited to only the embodiment illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGS. 1 and 2, an improved control system of this invention is generally indicated by the reference numeral 20 and includes a bake burner 21 and a broil burner 22 adapted to be disposed in a domestic cooking apparatus or the like to effect the cooking operation of a single cooking cavity or chamber by having a source of fuel 23 selectively directed thereto by a control device 24 of this invention in a manner hereinafter described.

As illustrated in FIGS. 1 and 2, the control device 24 includes a housing 26 having an inlet means 27 adapted to be fluidly interconnected to the fuel supply manifold 23 in any suitable manner and has an outlet means 28 interconnected to a conduit means 29 leading to the bake burner 21 and broil burner 22.

In particular, the conduit means 29 includes a first conduit 30 having one end 31 fluidly interconnected to the outlet 28 of the control device 24 and the other end 32 interconnected to an inlet 39 of a diverter valve means 40. An outlet means 44 of the diverter valve means 40 is interconnected to one end 36 of another conduit 37 of the conduit means 29 which has its other end 38 interconnected to an inlet 33 of a safety valve means 34.

The safety valve means 34 can be of the type disclosed in U.S. patent to Branson et al., No. 3,233,830, wherein the valve means 34 prevents fluid communication between its inlet means 33 and its outlet means 35 that is fluidly interconnected to the bake burner 21 when a flame detector means 41 senses that a certain flame means does not exist at a bake pilot burner means 42 for the bake burner 21. For example, the bake pilot burner means 42 can be of the type disclosed in the aforementioned US. patent to Branson et al. or of the type disclosed in the US. patent to Riehl, No. 3,308,871, wherein the same is adapted to be continuously supplied a small amount of fuel from the control device 24 through a conduit means 84 to maintain a continuously burning small standby flame which is not sensed by the detector means 41. However, when the bake pilot burner means 42 is additionally supplied fuel by the control device 24 through the conduit means 84 in a manner hereinafter described, the bake pilot burner means 42 creates a large heater flame that is detected by the detector means 41 to cause the safety valve 34 to open and remain open as long as such heater flame exists at the bake pilot burner means 42 to fluidly interconnect the conduit 37 with the bake burner 21.

The diverter valve means 40 has a pair of outlets 43 and 44 respectively interconnected to ends 45 and 36 of conduits 47 and 37 forming part of the previously described conduit means 29 and respectively having the other ends 49 and 38 thereof fluidly interconnected to the broil burner 22 and to the safety valve 34 for the bake burner 21.

The diverter valve means 40 is so constructed and arranged that a first valve member 51 is operated by a lever 46 and is normally biased to an open position thereof by a spring 48 to maintain the outlet means 44- normally opened. A second valve member 53 is also operated by the lever 46 and is normally biased by the spring 48 to be in a closed position to normally close the outlet means 43.

A movable wall 56 of a power element 57 for the diverter valve 40 is so constructed and arranged that when the same is in a collapsed condition, as illustrated in FIG. 1, the same, through the spring 48 and lever 46, permits the valve member '51 to be in an open position and the valve member 53 to be in a closed position. However, when the power element 57 is expanded for a broiling operation in a manner hereinafter described, the movable wall 56 thereof moves downwardly to first cause closing of the valve member 51 against the outlet means 44 before the movable wall 56 will cause opening movement of the valve member 53 away from the outlet means 43 for a purpose hereinafter described.

The interior of the power element 57 is interconnected to a bulb 59 by a capillary tube 60 so that when the bulb 59 senses that no certain flame means exists at a broil pilot burner means 61 for the broil burner 22, the power element 57 collapses and has the movable wall 56 thereof moved upwardly in FIG. 1 a suflicient distance so that the spring means 48 and lever 46 of the diverter valve means 40 will cause the valve member 51 to completely close the outlet means 43 of the diverter valve 40 and fully open the outlet means 44 thereof, However, when the certain flame means exists at the broil pilot burner means 61, the bulb 59 causes the power element 57 to expand in such a manner that movable *wall '56 thereof moves downwardly to first cause the valve member 51 to fully close the outlet means 44 of the diverter valve means 40 and, thereafter, cause the valve member 53 to move downwardly and fully open the outlet means 43.

The control device 24 of this invention is so constructed and arranged in a manner hereinafter set forth, that the control device continuously directs a small amount of fuel from the fuel source 23 to the pilot burner 61 through a conduit 62 to maintain a small flame 63 (FIG. 2) at the pilot burner 61. However, when the selector means 25 is set in a position for a broiling operation, the control device 24 directs an additional amount of fuel through the conduit means 62 leading to the broil pilot burner means 61 to create a large heater fiame 64 in addition to the flame 63 at the pilot burner 61.

The general operation of the control system illustrated in FIG. 1 will now be described.

When the selector means of the control device 24 is disposed in its off position, the control device 24 prevents the source of fuel 23 from being interconnected to the conduit of the conduit means 29 and also prevents any additional amount of fuel from being directed to the bake pilot burner means 42 through the conduit means 84 to create the previously described larger heater flame at the bake pilot burner means 42 whereby the safety valve means 34 is in a closed position to prevent fluid communication between the inlet means 33 and outlet means thereof even though a small standby flame is continuously burning at the bake pilot burner means 42. Also, when the selector means 25 of the control device 24 is disposed in its off position, no additional amount of fuel is directed by the control device 24 through the conduit means 62 leading to the burner pilot means 61 to create the previously described large heater flame 64 at the broil pilot burner 61 whereby the detector 59 causes the diverter valve to be disposed and maintained in the position illustrated in FIG. 1 wherein the valve means 53 closes off the outlet means 43 leading to the broil burner 22 and fully opens the outlet means 44 leading to the bake burner 21 even though no fuel is issuing thereto.

When the selector means 25 is moved to a position for a baking operation in a manner hereinafter described, the control device 24 does not supply any additional amount of fuel to the broil pilot burner means 61 whereby the diverter valve means 40 will remain in the position illustrated in FIG. 1. However, since the temperature in the oven is below the temperature selected by the selector means 25, the control device 24, in a manner hereinafter described, supplies an additional amount of fuel through the conduit 84 to create the previously described large heater flame at the bake pilot burner means 42 to be detected by the detector means 41 which will open the safety valve means 34 to interconnect the inlet means 33 thereof with the outlet means 35. Also, when the selector knob 25 is set at any on oposition, the same interconnects the source of fuel 23 with the conduit means 30 whereby fuel now can pass through to opened outlet 44 of the diverter valve 40 and through the opened safety valve means 34 to the bake burner 21 to be ignited by the bake pilot burner means 42.

The control device 24 continuously supplies fuel to the bake burner 21 to heat the oven until a temperature sensing bulb 85 of the control device 24 determines that the temperature of oven is at or above the temperature selected by the knob 25 whereby the control device 24, in a manner hereinafter described, will terminate the flow of the additional fuel through the conduit 84 leading to the bake pilot burner means 42 so that the heater flame at the bake pilot burner means 42 will no longer exist. Thus, the detector 41 will close the safety valve 34 to prevent fuel from being directed to the bake burner 21. However, when the temperature in the oven falls below the temperature selected by the knob 25, the bulb means 85 will again cause the control device 24 to create the large heater flame at the bake pilot burner means 42 to open the safety valve 34 in the manner previously described to permit fuel to again issue from the main burner means 21 and be ignited by the bake pilot burner means 42.

Thus, it can be seen that in any baking operation selected by the selector means 25 of the control device 24, the bake burner means 21 will be cycled on and off by the control device 24 to tend to maintain the temperature effect in the oven at the temperature effect selected by the selector knob 25, such baking operation not effecting the operation of the broil burner 22.

When the housewife or the like desires to utilize the control system 20 for a boiling operation, the housewife sets the selector knob 25 in a boiling position thereof in a manner hereinafter described whereby no additional amount of fuel is supplied by the control device 24 through the conduit means 84 to create the heater flame at the bake pilot burner means 42 to open the safety valve 34. However, an additional amount of fuel is directed by the control device 24 through the conduit 62 to the pilot burner 61 to create the large heater flame 64. The now continuously burning large heater flame 64 at the broil pilot burner means 61 is detected bythe detector means 59 to cause the movable wall 56 of the power element 57 to move downwardly in FIG. 1 and first close the outlet means 44 thereof before opening the outlet means 43 whereby the fuel being directed to the diverter valve means 40 by the control device 24 can only be directed by the diverter valve means 40 to the broil burner 22 and not to the bake burner 21.

Thus, the fuel issuing from the broil burner 22 by the diverter valve means 40 will be ignited by the broil pilot burner means 61 and will be continuously supplied fuel by the control device 24 to provide a continuous flame broiling operation.

The particular details of the control device 24 for effecting the above operation of the control system 20 will now be described.

The control device 24 includes a disc valve member 87, FIG. 2, interconnected to the selector means 25 so that when the selector means is moved to any on bake position thereof in a manner hereinafter described, the disc valve 87 not only interconnects the inlet 27 with the outlet 28, but also interconnects the inlet 27 with a passage means 88 leading to a chamber 89 defined by a valve seat member 90 carried by the housing 26. The chamber 89 is separated from a chamber 91 by a valve seat 92 on the valve seat member 90, the valve seat 92 being opened and closed by a valve member 94 urged to the closed position by a compression spring 95.

An axially movable fulcrum pin 96 is carried by the housing 26 in such a manner that the axial position of the fulcrum pin 96 relative to the housing 26 is con- 1 trolled by the selector or control knob 25 in a manner hereinafter described. The fulcrum pin 96 has a rounded end 97 provided with a cylindrical projection 98 passing through a suitable aperture in a lever 99 whereby the lever 99 is fulcrumed on the end 97 of the fulcrum pin 96.

One end 100 of the lever 99 bears against a movable wall 101 of an expansible and contractible element 102 having a wall 103 fixed to the housing 26, the interior of the expansible and contractible element 102 being interconnected to the oven temperature sensing bulb 85 by a conduit 104. The movable wall 101 of the expansible and contractible element 102 carries a valve member 105 for opening and closing a valve seat 106 in a manner hereinafter described.

The other end 107 of the lever 99 is adapted to engage a plunger 108 carried by the valve seat member 90 and engaging the valve member 94, the end 107 of the lever 99 being urged in a clockwise direction in FIG. 2 by a compression spring 109. Thus, the opening and closing of the valve member 94 is controlled by the lever 99 in relation to the temperature sensed by the bulb 85 and the axial position of the fulcrum pin 96 in a manner hereinafter described.

The chamber 91 of the housing 26 is interconnected to a passage means 110 leading to a bore 111 in the housing 26, an adjusting key 112 being rotatably disposed in the bore 111 and having a longitudinal bore 113 interconnected to the exterior of the key 112 by transverse bores 114 and 115. The longitudinal bore 113 of the adjusting key 112 is disposed in communication with a passage 116 leading to the conduit 84 interconnected to the bake pilot burner means 42.

Another passage 117 is formed in the housing 26 and is interconnected with the inlet passage 27 at a point upstream from the disc valve 87 as well as to a filter chamber 118. The filter chamber 118 is interconnected to a passage 119 leading to the bore 111 in the manner illustrated in FIG. 2, the passage 119 having an orifice 120 therein. The filter chamber 118 is also interconnected by a passage 113A having an adjusting key 118B therein to the conduit means 62 leading to the broil pilot burner 61.

Thus, it can be seen that when the adjusting key 112 is disposed in the on position, as illustrated in FIG. 2, fuel from the supply conduit 23 is adapted to pass through the passages 117 and 119 to the passage of the adjusting key 112 and, thus, to the bake pilot burner means 42 to provide the previously mentioned small standby flame, which does not affect the safety valve means 34. Also, fuel is continuously supplied through the passage 117, passage 118A and conduit means 62 to provide the previously mentioned small standby flame 63 at the broil pilot burner 61 which does not affect the diverter valve 40.

However, when the disc valve 87 is moved to an opened position for a baking operation and the valve member 94 is moved to an opened position in a manner hereinafter described, the additional fuel being supplied through the passage 110 to the passage 114 of the adjusting key 112 causes the bake pilot burner means 42 to provide the previously described large heater flame which is sensed by the bulb 41 and causes the safety valve means 34 to open. However, when the valve member 94 closes, the additional supply of fuel to the pilot burner 42 is terminated whereby the large heater flame ceases to exist, even though the small standby flame continues, whereby the safety valve 34 will close.

Thus, as the valve member 94 cycles between its opened and closed positions in a manner hereinafter described, the safety valve means 34 is cycled on and off to maintain the temperature of the oven at a temperature selected by the control knob 25 in the manner previously described.

As illustrated in FIGS. 4, and 6A the housing means 26 defines a fiat valve surface 121, interrupted by the spaced inlet 27 and an outlet 122 adapted to be interconnected together by a groove 123 in the disc valve 87.

In particular, the groove 123 in the disc valve 87 interrupts a valve surface 124 thereof with the valve surface 124 being disposed in sealing and sliding contact with the valve seatsurface 121 of the housing 26, the disc valve 87 having an opening 125 passing therethrough and loosely receiving the end 126 of the fulcrum pin 96.

As illustrated in FIG. 5, the disc valve 87 has a pair of spaced arcuate embossments 127 formed on the side 128 thereof and a smaller substantially rectangular embossment 129 intermediate the embossments 127 for a purpose hereinafter described.

A cup-shaped member 130 forms part of the housing means 26 and is telescopically disposed over the disc valve 87, the member 130 having an aperture 131 passing therethrough in the closed end 132 thereof. The closed end 132 has a cam slot 133 formed therein and defining opposed camming edges 134 and 135 best illustrated in FIGS. 6 and 7. In addition, a pair of apertures 136 pass through the wall 132.

A C-shaped shaft 137 has one end 138 thereof interconnected to a plate member 139 having three outwardly projecting tangs 140, 143 and 142. In addition, rearwardly directed tangs 141 are formed in the plate member 139 and are adapted to register with apertures 144 formed on another plate member 145.

The plate member 145 has a bent over tang 146 provided with a slot 147 and a pair of ears 148 having apertures 149 passing therethrough. The members 139 and 145 are adapted to be assembled together with another tang 150 of the member 139 received in the slot 147 of the member 145 and with the ears 148 of the member 145 passing through slots 151 of the plate member 139 and pinned thereto by a pin means 152 passing through the apertures 149. In this manner, rotation of the shaft 137 by the control knob 25 causes like rotation of the plate member 145.

The plate member 145 carries a tubular extension 153 both internally and externally threaded, the tubular extension 153 adapted to be threadedly received in a threaded bore 154 of a member 155 fixed in the aperture 131 of the housing part 130.

An adjusting screw 156 is threaded in the tubular part 153 of the plate 145 and has an end 157 adapted to abut the end 126 of the fulcrum pin 96.

Thus, rotation of the control knob 25 fastened on the other end 158 of the C-shaped shaft 137 causes the member 153 to be threaded into or out of the fixed threaded member 155 to adjust the axial position of the fulcrum pin 96.

A bowed spring-like washer 159 is provided and has tangs 160 adapted to register in the apertures 136 of the housing part 130, the spring means 159 having reversely directed tangs 161 adapted to be received in notches 162 in a washer-like member 163, the spring member 159 and washer-like member 163 being disposed between the closed wall 132 of the housing part 130 and the plate member 145 to place an outward force on the plate-like member 145, and, thus, provide feel in adjusting the rotational position of the knob 25 relative to the housing 26.

A spring retainer 164 is provided and has outwardly directed tangs 165 adapted to rest on the embossments 127 of the disc valve 87 and another tang 166. Another spring retainer 167 is provided and has an outwardly directed tang 168 similar to tang 166 of the spring retainer 164, retainers 164 and 167 respectively having openings 169 and 170 passing therethrough so that the same can be telescoped on the fixed threaded member 155. A compression spring 171 is adapted to be disposed between the spring retainers 164 and 167 to compact a clutch member 172 against the inside surface of the wall 132 of the housing part The clutch part 172 has a pair of depending flanges 173 defining a notch 174 therebetween adapted to not only receive the tangs 168 and 166 of the spring retainers 167 and 164, but to also receive the rectangular embossment 129 of the disc valve 87. In addition, the clutch member 172 has an outwardly directed tang 175 adapted to pass through the cam slot 133 of the housing part 130, the clutch part or drive member 172 having an aperture 176 passing therethrough to loosely receive the fixed member 155.

The operation of the control device 24 as utilized in the system 20 of this invention, with the parts heretofore described, will now be described.

Assuming that the control knob 25 is disposed in its off position as illustrated in FIGS. 2, 6, 6A and 6B, the groove 123 of the disc valve 87 is in such a position that the same does not interconnect the inlet 27 with the outlet 122 nor the inlet 27 with the passage means 88 whereby no fuel issues from the bake burner 21 and only small standby flames exist at the broil pilot burner means 61 and at the bake pilot burner means 42 as the adjusting key 112 is normally disposed in the on position as illustrated in FIG. 2.

When the operator desires to turn on the oven for a set baking temperature thereof, the operator graps the knob 25 and rotates the same in a counterclockwise direction as illustrated in FIG. 7 whereby rotation of the knob 25 causes like rotation of the plate 139 whereby the tang 140 of plate 139 bears agains the tang 175 of the drive member 172 to cause like rotation therewith. As the drive member 172 is being rotated, the same, through the notch 174 thereof, rotates the spring retainers 167 and 164 as well as the disc valve 87 to bring the groove 123 of the disc valve 87 in such a position that the same fully interconnects the inlet 27 with the outlet 122, as well as to have a groove 177 of the valve member 87 interconnect a branch inlet port 178 of the housing 26 to the passage 88 as illustrated in FIG. 7A.

However, when the disc valve 87 is rotated to its fully on position, it can be seen that the edge of the cam slot 133 slides the drive member 172 radially outwardly to the position illustrated in FIGS. 7 and 7B whereby the tang of the plate member 139 is no longer in engagement with the tang 175 of the drive member 172 so that the control knob 25, when further rotated in a counterwlockwise direction for setting the desired baking temperature does not further rotate the disc valve 87 from its fully on position as illustrated in FIGS. 7, 7A and 7B. Thus, the sliding movement of the drive member 172 declutches the disc valve '87 from the control knob or manipulator means 25.

During the rotational movement of the control knob 25 from its position to a set baking temperature position thereof, the threaded member 153 of the plate is backed out of the fixed threaded member in such a manner that the fulcrum pin 96 is adjusted to a new position thereof to the right in FIGS. 2, 3 and 4 as selected by the temperature setting of the control knob 25.

This axial movement of the pin 96 from its off positron to its selected baking temperature position permits the compression spring 109 to pivot the lever 99 on the fulcrum pin 96 in such a manner that the pin 108 carried by the valve seat member 90 is moved to the right in FIG. 2 to open the valve member 94 away from the valve seat 92 so that fuel in the passage 88 is now adapted to pass into the chamber 91 and, thus, to the bake pilot burner means 42 to create the large heater flame at the bake pilot burner means 42 whereby the bake burner 21 will be operated in the manner previously described.

Should a malfunction occur in the control device 24 of this invention, so that the valve member 94 Will not close whereby the bake burner 21 remains on in a runaway condition, the increased temperature in the oven will cause the movable wall 101 of the power element 102 to further move to the right in FIG. 2 to bring the valve member 105 closer to the valve seat 106 to throttle the flow of fuel to the bake burner 21 in such a manner that the bake burner 21 cannot produce a temperature in the oven above a predetermined safe temperature. Such safety feature also applies for the broiling operation hereinafter described.

When it is desired to turn off the system 20 of this invention, the operator rotates the control knob 25 back to the off position illustrated in FIG. 6. As the plate 139 is being rotated to its off position, the tang 142 thereof engages the tang 175 of the drive member 172 and rotates the drive member 172 therewith, whereby the disc valve 87 is rotated back to its off position, the drive mmeber 172 sliding radially inwardly relative to the disc valve 87 by means of the edge 134 of the cam slot 133 in the housing part 130 from the position illustrated in FIGS. 7 and 7A back to the position illustrated in FIGS. 6 and 6A. As the control knob 25 is rotated back to its off position, the tang 175 on the drive member 172 engages the end of the slot 133 when the control knob is disposed in its position whereby the cam slot 133 determines the off position of the control knob 25.

When it is desired to utilize the control system 20 of this invention for a broiling operation, the housewife or the like turns the selector means or control knob 25 in a counterclockwise direction in the manner previously described through the bake range until the control knob 25 as illustrated in FIG. 9 has the broil setting thereof placed adjacent the mark 179 on an outer stationary ring 180 of the housing means 26. As the control knob 25 is being slowly rotated and as the same approaches the broil setting thereof, it can be seen in FIGS. 8 and 8A that the tang 143 of the member 139 engages the tang 175 of the drive member 172 to rotate the same in a counterclockwise direction until the tang 175 engages the lower end of the cam slot 133 which is the broil position of the control knob 25. This further rotation of the drive member 172 causes further like rotation of the valve member 87 whereby the groove 177 of the valve member 87 only interconnects the branch inlet port 178 of the housing 26 with a passage means 181 in the housing means 26 that leads to the conduit 62 for the broil pilot burner means 61 to supply the additional amount of fuel to the broil pilot burner 61 to create the large heater flame 64.

The diverter valve 40 is now under the control of the large heater flame 64 of the broil pilot burner means 61 to divert the flow of fuel from the control device 24 to only the broil burner 22 to be operated in the manner previously described.

Since a normal broiling operation takes place at approximately 625 F. or the like, and since it is desired to produce a continuous flame broiling operation by the broil burner 22, should the temperature sensing bulb 85 sense that the temperature in the oven is exceeding the aforementioned 625 F. or the like, the movable wall 101 of the power element 102 moves to the right in FIG. 2 to cause the valve member 105 to produce a throttling down or modulating action on the flow of fuel passing through the valve seat 106 so that the flame at the broil burner 22 will not go out and will not tend to exceed the aforementioned 625 F. temperature in the oven for the system 20.

Therefore, it can be seen that this invention provides an improved control system for a double burner oven or the like as well as improved parts and method for such system or the like.

In addition, the system 20 overcomes a particular disadvantage of prior known all gas systems where both burners become operating under conditions of loss of control during a baking operation, such as by a broken temperature sensing bulb means 85 or the like.

In particular, the system 20 overcomes the above disadvantage while still providing the single dial operation for the bake and broil temperature settings in a manner not provided by prior known systems.

For example, under conditions of loss of control, such as by a broken thermostat bulb during a baking operation, only the bake burner 21 will be operated as the rise in temperature in the oven will not cause operation of the broil burner 22 as in prior known systems wherein a thermally operated broil safety valve will open when the oven temperature reaches a temperature sufiicient to cause the flame detector for the broil safety valve to open whereby for this prior known type of system, a separate main flow broil selector cock is normally required in addition to a selector cock for a baking operation.

However, in the control system 20, when such a high tempenature is reached, the diverter valve 40 acts first to reduce or modulate the input flow of fuel to the bake burner 21 because, as the movable wall 56 of the power element 57 moves downwardly, the valve member 51 approaches the outlet means 44 with a modulating or throttling action so that the temperature cannot rise sufficiently in the oven to cause the power element 57 to open the valve member 53 and permit fuel to be directed to the broil burner 22.

With the above description of the parts and operation of the system 20 in mind, the improved broil pilot burner means 61 of this invention will now be described.

In particular, it has been found that when the broil pilot burner means 61 has the small standby flame 63 continuously burning in the top part of the single cavity of the oven containing the main burners 21 and 22, a subsequent operation of the bake burner 21 or of the broil burner 22 for a cooking operation or the like creates sufficient combustion products in the oven that will tend to snuff out the small standby flame 63 of the broil pilot burner 61 whereby when the housewife or the like subsequently desires to provide a broiling operation a broiling operation cannot take place, as the diverter valve 40 will not permit fuel to flow to the broil burner 22 in a broiling position of the selector knob 25 since the pilot burner means 61 is not ignited.

Therefore, the broil pilot burner means 61 of this invention is formed in the manner illustrated in FIGS. 2 and 10-12 wherein a housing member 200 is provided and has an externally threaded tubular member 201 extending from one side 202 thereof with the tubular extension 201 having a passage means 203 passing therethrough and being fluidly interconnected to another passage means 204 of larger diameter that interrupts the opposed side 205 thereof. An orifice cup 206, FIG. 2, is disposed in the passage 203 of the tubular extension 201 and a threaded fastening member 207 is utilized to couple the end 208 of the conduit means 62 to the passage 203 of the tubular extension 201 in the manner illustrated in FIG. 2.

A transverse bore 209 is formed in the side 210 of the housing member 200 and is internally threaded to receive a threaded extension 211 of a fitting 212 that has another extension 213 adapted to fluidly interconnect a conduit means 214, FIG. 1, thereto for a purpose hereinafter described.

A conduit 215 has one end 216 thereof secured in the opening means 204 of the housing 200 so as to be in fluid communication with the passage 203 thereof downstream from the orifice cup 206, the conduit 215 being inwardly depressed at 217 to provide a restriction therein intermediate the end 216 and the other end 218 thereof which defines an outlet means 219 for the pilot burner means 61. A flame shield arrangement 220 is secured to the end 218 of the conduit 215 and has an opening 221 therein and through which the small standby flame 63 of the pilot burner means 61 can project and burn for subsequent igniting of the broil burner 22 when the same receives fuel from the diverter valve means 40 in the manner previously described. In addition, the flame shield 220 has downwardly projecting ears 222 provided with suitable opening means 223 therein which receive the detector bulb 59 for the diverter valve 40, the ears 222 be ing so constructed and arranged that the detector 59 is not influenced by the small standby flame 63, but will be disposed in the path of the large heater flame 64 when the control device 24 directs the additional amount of fuel to the pilot burner means 61 in the manner previously described for a broiling operation of the system 20, the flame shield 220 carrying a suitable fastening member 224 for securing the detector 59 in the openings 223 of the ears 222 thereof.

The bore 209 in the housing 200 is so constructed and arranged that the closed end 225 thereof extends beyond the conduit 215 as illustrated in FIG. 11. The end 216 of the conduit 215 is provided with an opening 226 therein that faces the closed end 225 of the bore 209 so that any air passing through the passage means 227 of the fittings 212 into the bore 209 of the housing 200 must pass around the end 216 of the conduit 215 in a direction transverse to the axis of the conduit 215 to enter into the flow passage of the conduit 215 at the opening 226 thereof so as to provide turbulence to such air movement before the same reaches the interior of the conduit 215 to be entrained in the fuel passing through the conduit 215 and being supplied thereto through the passage 203 of the housing 200 from the previously described conduit means 62.

The fitting 212 has a pair of openings 228 and 229 passing transversely therethrough to interconnect the exterior of the fitting 212 to the passage 227 thereof, the openings 228 and 229 being vertically aligned when the pilot burner means 61 is arranged in a position illustrated in FIG. 1 for a purpose hereinafter described.

As illustrated in FIG. 1, the conduit 214 that is interconnected to the fitting 212 of the broil pilot burner means 61 has its inlet end 230 interconnected to the outlet of an electrically operated air pumping device 231 that has its inlet 232 disposed in a location to be interconnected to a primary air source that is not subject to be contaminated by the combustion products created by either the bake burner 21 or the broil burner 22. For example, the inlet 232 of the air pumping device 231 can be connected to a primary air source that is outside of the oven cavity that contains the bake burner 21 and broil burner 22.

The electrically operated air pump 231 has one side 233 thereof interconnected by lead 234 to a power source lead L the other side 235 of the air pumping device 231 being interconnected by a lead 236 to one side 237 of a normally open electrical switch 238. The other side 239 of the electrical switch 238 is interconnected by lead 240 to the other power source lead L The electrical switch 238 can be so constructed and arranged that the same can be pressure operated to its closed position so that when any fuel is issuing into the outlet 28 of the control device 24 because of the selector knob 25 being in any on position thereof, the electrical switch 238 will close to place the air pumping device 231 across the power source leads L and L so that the air pumping device 231 will be continuously operating when the selector knob 25 is arranged in any on position thereof.

Alternately, and as illustrated in FIGS. 6A, 7A and 8A, the electrical switch 238 can be mechanically operated by the disc valve member 87 of the control device 24.

For example, the electrical switch 238 as illustrated in FIG. 6A can have a fixed contact 241 interconnected to the lead 240 and a movable contact 242 carried on a spring blade 243 that is electrically interconnected to the lead 236 and has a natural bias to hold the contact 242 away from the contact 241 as illustrated in FIG. 6A. However, the disc valve member 87 of the control device 24 has a cam means 244 on the side thereof so that when the disc valve member 87 is rotated to any bake position of the control device 24 by the control knob 25 in the manner previously described, the cam means 244 cams against the spring blade 243 to move the same as illustrated in FIG. 7A to place the movable contact 242 into electrical contact with the fixed contact 241 so that the air pumping device 231 will be placed across the valve source leads L and L and continuously operate as long as the control device 24 is set in any baking position thereof. Similarly, as illustrated in FIG. 8, even when the disc valve member 87 is moved to a broiling position thereof, the cam means 244 maintains the movable contact 242 in electrical contact with the fixed contact 241 to continuously operate the air pumping device 231 during the entire broiling operation.

The operation of the broil pilot burner means 61 of this invention will now be described.

With the control device 24 set in the off position there of, no combustion products are being created in the oven containing the bake and broil burners 21 and 22 which would tend to snuff out the continously burning small standby flame 63 of the broil pilot burner 61 whereby it is not necessary that the air pumping device 231 be operating. Thus, with the control device 24 set in the off position as illustrated in FIG. 6A, the electrical switch 238 is in an open position so that the air pumping device 231 is not energized.

However, since a small amount of fuel is being continuously directed through the conduit 62 to the broil pilot burner means 61, such flow of fuel through the conduit 215 causes primary air adjacent the fitting 212 to be drawn through the openings 228 and 229 of the fitting 212 through the bore 209 of the housing 200 to the opening 226 of the conduit 215 to be entrained in the fuel passing through the conduit 215 to supply sufficient primary air to be mixed with the fuel to sustain combustion at the outlet end 219 of the conduit 215 whereby the continuously burning small standby flame 63 will be provided for the pilot burner means 61.

However when the selector knob 25 of the control device 24 is set in any on position thereof, the switch 238 is closed in the manner previously described so that the air pumping device 231 is continuously operating and forcing primary air that is not contaminated with any combustion products of the oven containing the burner means 2]. and 22 into the conduit means 214 under pressure so that the same is forced into the fitting 212 at the end 213 thereof to be forced into the opening 209 of the housing 200 and be fed to the opening 226 in the conduit 215 to be entrained in the fuel passing therethrough to supply sufficient primary air to maintain the small standby flame 63 of the broil pilot burner means 61 or the large heater flame 64 thereof even though the secondary air being supplied to the end 219 of the conduit 215 is now contaminated with combustion products in the oven of the cooking apparatus, the force of the primary air by the air pumping device 231 through the fitting 212 creating an air pressure in the fitting 212 greater than the air pressure surrounding the fitting 212 so that no combustion products adjacent the fitting 212 can enter the openings 228 and 229 thereof to contaminate the primary air being fed to the pilot burner means 61 by the air pumping device 231. For example, the air pumping device 231 can supply primary air at a rate of .1 inch WC for the above purpose.

Therefore, it can be seen that the pilot burner control means of this invention insures that during any on condition of the oven, the broil pilot burner means 61 will be supplied suflicient primary air to maintain combustion at the pilot burner means 61 and that when the oven is in an off condition, sufficient primary air is still supplied thereto to sustain combustion at the broil pilot burner means 61.

Accordingly, it can be seen that this invention not only provides an improved pilot burner control system or the like, but also this invention provides an improved method of operating such a pilot burner control system or the like.

What is claimed is:

1. In a fuel control system having a source of fuel and control means for selectively interconnecting said source of fuel to a bake burner and a broil burner respectively disposed in the same oven cavity or the like, the improvement comprising a pilot burner for igniting said broil burner, means for continuously interconnecting said source of fuel to said pilot burner, and means for interconnecting a primary air source that is not contaminated with combustion products of said oven to said pilot burner to entrain with the fuel therefor only when said control means is directing said source of fuel to at least one of said bake burner and said broil burner to produce combustion products in said oven.

2. In a fuel control system as set forth in claim 1, the further improvement wherein said means for interconnecting said primary air source to said pilot burner comprises an air pumping device.

3. In a fuel control system as set forth in claim 2, the further improvement wherein said air pumping device is electrically operated, said control means having electrical switch means which energizes said air pumping device to deliver said primary air when said control means is set for delivering fuel to at least one of said bake burner and said broil burner.

4. In a fuel control system as set forth in claim 1, the further improvement wherein said means for interconnecting said primary air source to said pilot burner interconnects said pirmary air source to said pilot burner when said control means directs said fuel source to either said bake burner or said broil burner.

5. In a fuel control system as set forth in claim 1, the further improvement wherein said means for continuously interconnecting said source of fuel to said pilot burner creates a small standby flame at said pilot burner.

6. In a fuel control system as set forth in claim 5, the further improvement wherein said control means has means for supplying an additional amount of fuel from said source of fuel to said pilot burner to produce larger flame means at said pilot burner when said control means is set to deliver fuel to said broil burner.

7. In a fuel control system as set forth in claim 1, the further improvement wherein said pilot burner has first conduit means for receiving said fuel from said means for continuously interconnecting said source of fuel to said pilot burner, said first conduit means having outlet means for creating flame means by the burning of said fuel issuing therefrom, said means for interconnecting said primary air source to said pilot burner means comprising second conduit means fluidly interconnected to said first conduit means.

8. In a fuel control system as set forth in claim 7, the further improvement wherein said second conduit means has opening means therein to interconnect the atmosphere in said oven cavity to said second conduit means.

9. In a fuel control system as set forth in claim 8, the further improvement wherein said opening means in said second conduit means are so constructed and arranged that said opening means deliver primary air to said first conduit means to be entrained in said fuel being delivered by said means continuously interconnecting said source of fuel to said pilot burner only when said means for interconnecting said primary air source to said pilot burner is not interconnecting said primary air source to said pilot burner.

10. In a fuel control system as set forth in claim 9, the further improvement wherein said means for interconnecting said primary air source to said pilot burner comprises means for creating a primary air pressure in said second conduit means greater than the air pressure in said oven cavity whereby said primary air pressure in said second conduit means prevents the atmosphere in said oven cavity from entering said opening means of said second conduit means when said primary air source is interconnected to said pilot burner.

11. In combination, a pilot burner for igniting a main burner associated with said pilot burner, a main burner, first conduit means interconnected to said pilot burner adapted to continuously supply fuel to said pilot burner for creating certain flame means at said pilot burner, second conduit means interconnected to said pilot burner, selector means for interconnecting a fuel source to said main burner and for disconnecting said fuel source from said main burner, and means adapted to force primary air into said second conduit means to be entrained in the fuel being supplied to said pilot burner, said last-named means and said selector means being so constructed and arranged that said last-named means only forces air into said second conduit means when said selector means is in an on condition thereof.

12. A combination as set forth in claim 11 wherein said means adapted to force primary air into said second conduit means comprises an air pumping device.

13. A combination as set forth in claim 11 wherein said second conduit means is disposed in fluid communication with said first conduit means.

14. A combination as set forth in claim 13 wherein said second conduit means has opening means therein to interconnect the atmosphere to said second conduit means.

15. In combination, a pilot burner for igniting a main burner associated with said pilot burner, first conduit means interconnected to said pilot burner adapted to continuously supply fuel to said pilot burner for creating certain flame means at said pilot burner, second conduit means interconnected to said pilot burner, and means adapted to force primary air into said second conduit means to be entrained in the fuel being supplied to said pilot burner, said second conduit means being disposed in fluid communication with said first conduit means, said second conduit means having opening means therein to interconnect the atmosphere to said second conduit means, said opening means in said second conduit means being so constructed and arranged that said opening means delivers primary air to said first conduit means to be entrained in the fuel being delivered to the pilot burner by the first conduit means only when said means for forcing primary air into said second conduit means is not forcing primary air into said conduit means.

16. A combination as set forth in claim 15 wherein said means for forcing primary air into said second conduit means creates a pressure in said second conduit means greater than the pressure of the air surrounding the exterior of said opening means whereby said air pressure in said second conduit means prevents the air exterior to said opening means from entering said opening means when said means forces primary air into said second conduit means.

17. In a method for controlling the flow of fuel from a source of fuel to a bake burner and a broil burner respectively disposed in the same oven cavity or the like, the improvement comprising the steps of continuously directing said source of fuel to a pilot burner for the broil burner to provide continuous flame means at the pilot burner, and directing a primary air source that is not contaminated with combustion products of said oven to said pilot burner to entrain with the fuel therefor only when said source of fuel is being directed to at least one of said bake burner and said broil burner to produce combustion products in said oven.

18. In a method as set forth in claim 17, the further improvement wherein said step of directing said primary air source to said pilot burner comprises the step of pumping said primary air to said pilot burner.

19. In a method as set forth in claim 17, the further improvement wherein said step of continuously directing said source of fuel to said pilot burner comprises th step of directing said source of fuel to said pilOt burner through a first conduit means that has an outlet means for creating said flame means by the burning of said fuel issuing therefrom, and wherein said step of directing said primary air to said pilot burner means comprises the step of directing said primary air through a second conduit means that is fluid interconnected to said first conduit means.

20. In a method as set forth in claim 19, the further improvement comprising the step of forming opening means in said second conduit means to interconnect the atmosphere in said oven cavity to said second conduit means.

21. In a method as set forth in claim 20, the further improvement wherein said step of forming said opening means in said second conduit means forms said opening means in such a manner that said opening means deliver primary air to said first conduit means to be entrained in said fuel being delivered to said pilot burner only when said primary air source is not being interconnected to said second conduit means.

22. In a method as set forth in claim 21, the further improvement wherein said step of interconnecting said primary air source to said second conduit means comprises the step of creating a primary air ressure in said second conduit means greater than the air pressure in said oven cavity whereby said primary air pressure in said second conduit means prevents the atmosphere in said oven cavity from entering said opening means of said second conduit means when said primary air source is interconnected to said pilot burner.

23. A method for controlling a pilot burner that is utilized for igniting a main burner associated with said pilot burner, said method comprising the steps of continuously supplying fuel to said pilot burner through a a first conduit means for creating certain flame means at said pilot burner, and forcing primary air into a second conduit means leading to said pilot burner so that said primary air will be entrained in the fuel being supplied to said pilot burner by said first conduit means, said lastnamed step only taking place when a selector means for interconnecting a fuel source to said main burner and for disconnecting said fuel source from said main burner is in an on condition thereof.

24. A method as set forth in claim 23 wherein said step of forcing primary air into said second conduit means comprises the step of forcing said primary air into said conduit means by an air pumping device.

25. A method as set forth in claim 23 and including the step of disposing said second conduit means in fluid communication with said first conduit means.

26. A method as set forth in claim 25 and including the step of forming opening means in said second conduit means to interconnect the atmosphere to said second conduit means.

27. A method for controlling a pilot burner that is utilized for igniting a main burner associated with said pilot burner, said method comprising the steps of continuously supplying fuel to said pilot burner through a first conduit means for creating certain flame means at said pilot burner, forcing primary air into a second conduit means leading to said pilot burner so that said primary air will be entrained in the fuel being supplied to said pilot burner by said first conduit means, disposing said second conduit means in fluid communication with said first conduit means, and forming opening means in said second conduit means to interconnect the atmosphere to said second conduit means, said step of forming said opening means in said second conduit means causing said opening means to be so constructed and arranged that said opening means delivers primary air to said first conduit means to be entrained in the fuel being delivered to the pilot burner by the first conduit means only when said primary air is not being forced into said second conduit means.

28. A method as set forth in claim 27 wherein said step of forcing primary air into said second conduit means creates a pressure in said second conduit means greater than the pressure of the air surrounding the exterior of said opening means whereby said air pressure in said second conduit means prevents the air exterior to said opening means from entering said opening means when said primary air is being forced into said second conduit means.

References Cited UNITED STATES PATENTS 1,853,568 4/1932 Morick 431-285 2,096,369 10/1937 Berning 431--354 3,160,401 12/1964 Wollner 43l278X 3,320,943 5/1967 Crannell et al. 12639E 3,338,231 8/1967 Lamar 126-39E 3,376,862 4/1968 Riehl 12639E 45 CARROLL B. DORITY, IR., Primary Examiner 

